Invalid Emails Guide

How do you prevent invalid emails from being added to your email list?

Whether you're aware of it or not, invalid emails are in your database and mailing lists. Learn where they come from and how email list hygiene plays a role.

A bearded man in glasses looks on in thought as he says that 'candice@company' is an invalid email address.

Frequently asked questions

An invalid email address is any address that cannot receive an incoming email message. An email address might be invalid for a variety of reasons, including invalid syntax or format, typos, a nonexistent username or domain, or a configuration that doesn't accept incoming emails.

Invalid Emails Guide

How do you prevent invalid emails from being added to your email list?

Whether you're aware of it or not, invalid emails are in your database and mailing lists. Learn where they come from and how email list hygiene plays a role.

Email is the go-to method of communication for businesses. But just like with phones or mailing addresses, you need to ensure you have the correct data to connect with your customers and leads.

Any inaccurate, expired, or fake data are considered invalid emails.

But how exactly does an email expire and become invalid? Let's examine the possible causes, as messaging invalid email addresses can have severe consequences.

Why do emails become invalid?

Some email addresses are always invalid. For example, an email address that doesn't use the required syntax is considered invalid.

An explanation of email address structure, which includes the username, separator, domain name, and top-level domain.

Additionally, an email address is considered an invalid email if the username or domain doesn't exist or contains typos. These email addresses are always considered invalid.

However, an email address can also become invalid if the domain owner deletes the address. There are various reasons why this may happen:

The email address has been inactive for an extended period.
Promotions, job changes, or reassignments may prompt the business domain owner to delete or update email addresses.
The email address is no longer set up to receive incoming emails.

Invalid emails constantly appear due to email list decay. In fact, almost 28% of the average email list will decay annually. One in four valid email addresses found on your list may become invalid emails. This happens irrespective of business or industry type.

A woman in a polka-dot shirt looks at her laptop which shows that her contact John Smith has an invalid email address.

What happens if you email an invalid email address?

The immediate result of emailing an invalid email address is a hard bounce. Because no mailbox exists, the provider will send you your email with a return message.

The occasional hard bounce is inevitable. However, invalid emails are far more of a concern for businesses and other mass email senders. If too many outbound emails bounce (more than 2% of sent emails), it can damage your email sender reputation.

Think of your sender reputation as a credit score for your business mailing domain and IP address. To send more emails successfully, you need a positive reputation. If your reputation is negative, internet service providers will trust your emails less and be more likely to send your emails to spam. ISPs may also reject your emails, resulting in more bounces.

In other words, invalid emails hurt your email deliverability.

How to detect and prevent invalid emails from entering your database

To prevent invalid emails from worsening your sender reputation, you need to detect invalid emails with email verification.

Email verification or email list hygiene tools can verify and validate email addresses. Signup forms and CMS systems will often contain a basic regex checker, but this only detects errors in syntax. You'll need a more advanced validation method to ensure that the email address exists and is configured to receive incoming email messages.

Here's how more advanced email verification systems work:

You enter any email address or upload a list of email addresses to the service.
The verification tool begins a series of checks. It will examine the syntax of the address, DNS records, and SMTP configuration, which verifies the existence of the email address and the proper setup. If it fails any of these checks, it's considered an invalid email. If it includes such a feature, it may also check for other high-risk signifiers, such as a disposable domain or spam complaint abuse.
The email verifier returns your results and separates your invalid emails from the valid ones. You can then safely upload this list of clean contacts to your database and begin sending your email campaigns once more.

As a business owner or marketer, you're likely acquiring new email addresses through common marketing mediums like your newsletter signup or landing pages. You can also add a real-time email verification tool to those registration forms to prevent invalid emails from making it through.

Paid email verification platforms typically include real-time verification APIs. Ensure that the provider offers this feature before selecting the right service for your team.

The ZeroBounce email validation menu with a pop-up for the contact 'Candice Hurst,' which has the verified email address 'candice.hurst@company.com.'

How to maintain a valid email list

Invalid emails are prevalent everywhere. Valid emails on your list can become invalid over time, and new data sources frequently provide you with invalid or other high-risk email address types.

As a result, the only way to maintain a valid email list is through proactive effort. Here are our recommendations on how to prevent invalid emails from cluttering up your database:

Always validate new email addresses or lists obtained from business or marketing events.
Be careful when purchasing lists - Though many providers claim to sell safe data, there's a strong likelihood that they're selling the same expired data frequently. Email service providers also have ways of detecting these recycled lists and can suspend your account immediately.
Use real-time email verification wherever you have signup forms - This will automatically detect invalid emails before they enter your lists.
Perform periodic email list cleanings - At a minimum, aim to validate email addresses on your list once per quarter. Depending on the volume of email data you process regularly, you may want to increase your list hygiene efforts.

Frequently asked questions

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A man in a yellow hooded sweatshirt smiles wide with his eyes closed.

Invalid Emails Guide - What They Are and How to Prevent Them

Email is the go-to method of communication for businesses. But just like with phones or mailing addresses, you need to ensure you have the correct data to connect with your customers and leads.

Any inaccurate, expired, or fake data are considered invalid emails.

But how exactly does an email expire and become invalid? Let's examine the possible causes, as messaging invalid email addresses can have severe consequences.

Why do emails become invalid?

Some email addresses are always invalid. For example, an email address that doesn't use the required syntax is considered invalid.

Additionally, an email address is considered an invalid email if the username or domain doesn't exist or contains typos. These email addresses are always considered invalid.

However, an email address can also become invalid if the domain owner deletes the address. There are various reasons why this may happen:

The email address has been inactive for an extended period.
Promotions, job changes, or reassignments may prompt the business domain owner to delete or update email addresses.
The email address is no longer set up to receive incoming emails.

What happens if you email an invalid email address?

The immediate result of emailing an invalid email address is a hard bounce. Because no mailbox exists, the provider will send you your email with a return message.

In other words, invalid emails hurt your email deliverability.

How to detect and prevent invalid emails from entering your database

To prevent invalid emails from worsening your sender reputation, you need to detect invalid emails with email verification.

Here's how more advanced email verification systems work:

You enter any email address or upload a list of email addresses to the service.
The verification tool begins a series of checks. It will examine the syntax of the address, DNS records, and SMTP configuration, which verifies the existence of the email address and the proper setup. If it fails any of these checks, it's considered an invalid email. If it includes such a feature, it may also check for other high-risk signifiers, such as a disposable domain or spam complaint abuse.
The email verifier returns your results and separates your invalid emails from the valid ones. You can then safely upload this list of clean contacts to your database and begin sending your email campaigns once more.

Paid email verification platforms typically include real-time verification APIs. Ensure that the provider offers this feature before selecting the right service for your team.

How to maintain a valid email list

Invalid emails are prevalent everywhere. Valid emails on your list can become invalid over time, and new data sources frequently provide you with invalid or other high-risk email address types.

As a result, the only way to maintain a valid email list is through proactive effort. Here are our recommendations on how to prevent invalid emails from cluttering up your database:

Always validate new email addresses or lists obtained from business or marketing events.
Be careful when purchasing lists - Though many providers claim to sell safe data, there's a strong likelihood that they're selling the same expired data frequently. Email service providers also have ways of detecting these recycled lists and can suspend your account immediately.
Use real-time email verification wherever you have signup forms - This will automatically detect invalid emails before they enter your lists.
Perform periodic email list cleanings - At a minimum, aim to validate email addresses on your list once per quarter. Depending on the volume of email data you process regularly, you may want to increase your list hygiene efforts.

Invalid Emails Guide

How do you prevent invalid emails from being added to your email list?

Frequently asked questions

Invalid Emails Guide

How do you prevent invalid emails from being added to your email list?

Why do emails become invalid?

What happens if you email an invalid email address?

How to detect and prevent invalid emails from entering your database

How to maintain a valid email list

Contents

Frequently asked questions

Improve your company's email deliverability fast

Improve your company's email deliverability fast

Why do emails become invalid?

What happens if you email an invalid email address?

How to detect and prevent invalid emails from entering your database

How to maintain a valid email list

Contents